i'm working on a high-rez poly character (40,000 quads). i've decided to dump using influence objects 'cause they're too slow to update, although i can get away with using a couple of them so long as i just trans/rot/scale them and don't morph them.

so far i've got about 20 blendshapes SDK'd as joint fixes which work great, pretty quick as well. however that solution can't be SDK'd at the shoulders where the joint turns in multiple axis. i should be able to get a solution using either multiple sculpt deformers (yuk), or wire deformers on shoulder vertice sets would be my ideal solution....

anyway the actual question: can anybody give me an idea of the performance hit of these methods if someone has tried them...? on a *highrez* model obviously... or if you have a better solution feel free to share it :)

cheers.

poly-phobic

01 January 2005, 04:57 PM

influence objects slow??
i've use on meshes higher than 40k and not seen any slow downs. unless u also use the shape node as well as transform to deform your object. that might slow it down somewhat.
as for the elbow, i think its fairly simple, one blendshape for each rotation axis. one at 90 in z maybe 45 in +-y as for x, your shoulder does not rotate pasat your body when its down.
and also your shoulders, after that initial rotate 90 inz, anymore rotation after that is handled by the clavicle joints. so u can add few shapes to be driven by that.

In terms of speed optimizzation, i find influence low rez poly objects to be very fast and udates accordingly.

good luck.

Arcon

01 January 2005, 09:07 PM

the problem with using blendshapes at the shoulders is regardless of how realistic the blend poses are modelled, shoudlers have a reasonably wide range of motion and i'm finding that the problem is defining a relationship between the extreme poses... because the rotations of the joints that drive the poses tend to mix with each other and cause the blends to multiply each others effect.

for example: assuming the driver arm's Zrotation is forward, and X is a twist. when arm is forward (Z:90, 1st blend), how do you switch to another extreme at Z:90, X:40...? is arm Xrot the driver for the 2nd blend...? if so then the first blend will still be activated because Z is still 90, and the blends will combine and screw up the shoulder :( have you come accross this problem in the past..?

my problem with blends is really only a logistical problem in setting up the relationships for multiple axis like this... i would hope to get a solution going for this because blends are cool :)

Arcon

01 January 2005, 10:32 PM

influence objects slow??
In terms of speed optimizzation, i find influence low rez poly objects to be very fast and udates accordingly.
good luck.
to make influence objects work [when they are blendshaped], u have to enable 'use components' on the skin - is that correct...? if so, as soon as that happens there is a slowdown of up to 200% when scrubbing in the timeline. i'm not talking about just moving around influence objects, in that scenario they are a fine solution.

poly-phobic

01 January 2005, 11:05 PM

for example: assuming the driver arm's Zrotation is forward, and X is a twist. when arm is forward (Z:90, 1st blend), how do you switch to another extreme at Z:90, X:40...? is arm Xrot the driver for the 2nd blend...? if so then the first blend will still be activated because Z is still 90, and the blends will combine and screw up the shoulder :( have you come accross this problem in the past..?

my problem with blends is really only a logistical problem in setting up the relationships for multiple axis like this... i would hope to get a solution going for this because blends are cool :)
u can script the raltionship instead of using sdk to work around the extreme issues.

and instead of keying at an extreme position i key the blends incrementally, maybe one at 45 and then 90.
so here i think MEL would be perfect for this, and its relatively simple scripting.

u can also try using sculpt deformers.

Arcon

01 January 2005, 03:56 AM

u can script the raltionship instead of using sdk to work around the extreme issues.
so here i think MEL would be perfect for this, and its relatively simple scripting.

without giving an example that's not much help.... i tried using expressions to control the nodestate of the blend channels, but there must be a better solution than that. just for the small example i mentioned above, any idea of how a basic mel control would look...? any help would be greatly appreicated.

seven6ty

01 January 2005, 04:07 AM

Yeah, I'd be interested to hear about the MEL approach vs. SDK activation as well.

I've just started using multiply/divide nodes instead of expressions and I've found that to be much much quicker in that regard. So I'm thinking a node based activation would have to be much quicker to execute than a script activation as well. I'm skinning the same area as well Paul, but like I showed you I'm going more with poly influence blend shapes, which works really well for me and so I haven't had any overlapping issues of that nature. I should have the rig pretty much finished up soon, in the next couple of days and I'll let you have a look at it.

Arcon

01 January 2005, 05:47 AM

I should have the rig pretty much finished up soon, in the next couple of days and I'll let you have a look at it.
cool looking forward to seeing it :) yeah i might have got it sorted with influences on the shoulder too ;) they aren't blendshaped influences though, just moved around with SDK. seems to work quite well as long as i have patience in setting up the SDKs each side.... oh well at least its easy to mirror the weights ;)

thanks for your replies guys and hopefully the character will be ready to go soon.

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